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Diagnosing Psoriasis – Clinical Features and Types

Approximately 2% of the US population suffers from psoriasis. Psoriasis is a chronic skin disorder that occurs when the immune system overreacts to certain conditions which speeds up the skin’s cellular turnover rate. As a result, the skin thickens and becomes inflamed.

Psoriasis Types

Psoriasis is usually clinically identified, though lab testing is sometimes necessary. Psoriasis can take on one of several forms, and does not occur at the same time as another form.

Chronic plaque psoriasis is the most common, found in roughly 8 out of 10 patients. Thick patches of skin are found on extensor surfaces such as the elbows and knees, and also on the scalp and lower back.

Guttate psoriasis occurs in less than 2% of cases, and manifests as small raised bumps on the skin. These are usually found on the torso, limbs, and scalp. Guttate psoriasis is often preceded by streptococcal infection, and a third of these cases develop chronic plaque psoriasis.

Pustular psoriasis is characterized by clusters of sterile pustules, usually found on one’s palms and soles of their feet, but can be generalized as well. It is rare and quite unstable, requiring frequent hospital visits. Sudden withdrawal of certain medications – especially steroids – can instigate this condition.

Psoriatic nail disease affects nail formation, resulting in a thickened, yellowish, and flakey nail, and onycholysis (separation of the nail from the nail bed).

Complications of Psoriasis

The skin is considered the largest organ of our bodies, playing a considerable role in shielding against infection and maintaining temperature and hydration levels. When the skin is compromised by psoriasis, serious complications, related to a lack of these functions, may occur.

Psoriatic arthritis occurs in up to 30% of patients with psoriasis, but only 11% of these cases are properly diagnosed and treated.

Psoriasis Treatment

While there currently is not a cure for psoriasis, some oral therapies have been traditionally used for general systemic immune suppression. As scientists are continuing to study the relevant immune pathways involved in its development, anti-psoriatic biologics that target specific immune receptors are also available. Most recently, a drug called Stelara (ustekinumab), has been approved by the FDA for the treatment of psoriasis. It works by blocking proteins implicated in the excessive immune response involved in this condition.

Other treatment options include topical medications and phototherapy.

Risk Factors

Risk factors include some medications, endocrine factors, and obesity. In what is known as the Koebner phenomenon, trauma to the skin can also instigate psoriasis.

While gender is not a risk factor, family history is. A more direct family history of psoriasis correlates to a greater susceptibility. Although the precise etiology of this condition is not known, genetic pathways which are strongly linked to psoriasis have been identified. For example, the HLA-Cw6 allele, or PSORS1 gene, and 6 other loci (PSORS2 through 7) are highly implicated in psoriasis patients. Scientists continue to study genetics, other risk factors, and use animal models to test new treatments in order to improve the lives of psoriasis patients.